


Curiosity

by orphan_account



Category: Underfell - Fandom, Undertale (Video Game)
Genre: Alphys Needs a Hug, Alternate Universe - Underfell, Dom Sans, Dom W. D. Gaster, F/F, F/M, Gaster is a dick, Implied/Referenced Self-Harm, Light Dom/sub, New Souls, Reader Is Not Chara, Smut, Souls, Underfell W. D. Gaster, Videos of Sex
Language: English
Status: In-Progress
Published: 2017-04-12
Updated: 2017-04-15
Packaged: 2018-10-18 07:37:02
Rating: Explicit
Warnings: Rape/Non-Con
Chapters: 6
Words: 8,434
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/10612254
Author URL: https://archiveofourown.org/users/orphan_account/pseuds/orphan_account
Summary: All the colors have been found, Gaster is sure of it. He's sure.....until a girl drops down with a soul color he's never seen before.





	1. Determination?

**Summary for the Chapter:**

> A human has been spotted. But the scanner can't seem to figure out what kind of soul it is.

Gaster decided to take a little tour down the lab, specifically to see Alphys. He had heard the rumors already spreading; There was a new human spotted in Snowdin. 

The usual office gossip had no place in his workspace, but he admits, it gets vital information around quickly. So it was useful to some extent, even if he didn't like it.

Monsters were making bets. "How long until Gaster gets them?" "How were they going to react?". And the most hot topic of them all, "What color was their soul?"

Lately, the humans that fell, little they were, had all been boring. It was usually Kindness, Patience, maybe a Perseverance here and there. For a long time, it was all the same. 

They were looking for a Determination, and kept getting nothing.

Alphys, shy though she was, could do absolutely sickening things with these souls. She would lock the humans in her lab, depriving them of everything. Food, water, even social interaction was taken from them. 

A cruel way of living, but a necessary one. She would feed them these slabs of.....something. They looked like they had meat in them, and smelled terrible. Gaster tried one of them once. He still cringes at the thought of it. It was salty beyond comprehension. It was terrible. Good thing he wasn't the one eating them.

Either way, she had, or was getting close to, finding a way of bonding with these souls. She used a method involving Stockholm Syndrome. 

The souls would be so desperate for some level of sympathy, she could take any monster off the road, and the human would bond with them immediately.

But, not only does this take a long time, especially with souls that were Purple, Light Blue, or Orange, but it only lasted a few minutes before the human burned out, taking the monster with them. 

The underground had lost many monsters before Alphys decided that it wasn't enough. They had to bond over a different method.

States of Isolation, high stress and.......other, more......primal methods could be used. She didn't want to use the last one until absolutely needed.

Gaster wasn't above it though. He would do whatever it took to set his people free.

He marched down to the lab, keeping his head up at all times. There were monsters who would dust him if given the chance, and he wanted them to stay in place.

Once there, he knocked loudly on the large metal door. Alphys was usually watching documentaries on humans. They aren't the same as they were back then.

Back during the war, they would've dusted him without a second thought. Now.....they seem very colorful.

Always jumping about, running late for school, and eating things very strangely. 

Alphys answered immediately, a worrying sign indeed. 

"Gaster! Come quick! I was just about to call you!"

"What is it? Code Red? Does the human have a red soul?"

"Worse sir! I'm afraid I don't know what it is!"

"What do you mean?"

"I've never seen a soul like it! I've never seen this color before!"

Gaster looked at the human, then at the scanner they put it. It analyzed how humans behaved over a short period of time, then told you what it was most likely.

But the scanner was acting wonky. It wouldn't give a straight answer. He punched in a code, and it spat out some information. Specifically, what it thought the soul was originally. If it was close enough to Determination, they could still use it. This was highly uncommon, but sometimes souls were two colors at once. But. No?

It was first Patience, then Determination for just a minute. Then, it got stuck on a soul it didn't recognize.

He crumpled up the paper angrily. It had some level of Determination in it, and he wasn't gonna let this human slip through his fingers like the last one did.

He gritted his teeth and finally spoke. "Get. Sans."

He heard an audible gasp. "Sir. Are you sure? Is Sans the best-"

"That wasn't a question. Get. Sans. This is the last time I say it before there are consequences. You. WILL. Do what I say. Understand?"

Alphys squeaked loudly. He saw her bow low out of the corner of his eye. "Y-yes s-sir."

He kept staring at the human. She seemed to stop frequently, looking at things, but never touching them. She didn't seem tense, especially not for being in a new place. She didn't seem scared.

"I wonder...?"

**Notes for the Chapter:**

> Hey, so smut gets a LOT of hits, and I generally enjoy writing it! But I hate forcing it. So, if I don't feel like writing it, I won't (unless someone requests it!)
> 
> But, hey, I got the midnight smut feels, and M' gonna try and finish this one :)


	2. Obedient

**Summary for the Chapter:**

> Maybe Sans wasn't the best for this, but he does get the job done.......just in his own way.

You kept walking down the long purple hallway. Your quiet footsteps only made the smallest of echoes along the brick walls. 

After getting past the blazing fires of a goat demon, she hugged you and sent you down here, closing, and presumably locking the doors behind you.

You say "blazing fires of a goat demon", but she really wasn't that bad. Yeah, at first, she came out of nowhere and attacked you.

But she got confused when you didn't fight back or cower in fear. She invited you in for blood tea. You politely declined the tea, but agreed to sit down and have a lovely chat with her. 

The walk was long, and had some 'puzzles' along the way. She guided you through them, how nice of her, and, after complementing her lovely house, she sat you down in a fully furnished living room.

She had several questions for you. For starters, why weren't you afraid of her? It didn't seem like that big of a deal to you, but it was practically the only thing she talked about. 

She told you about all the humans that had fallen. They had all either tried to fight back, or had cowered in fear. You had done neither, rather, you smiled at her.

No fear, no aggression, nothing.

She found it rather strange. You shrugged it off as being fearless.

Later that night, or day, you don't know how time works down here, she lead you down to the basement, and hugged you. She told you to go through these doors, and to not speak of her again.

That led you to where you were, approaching two huge doors, with strange symbols on them. You cocked your head to the side, examining them. You could've swore you had seen them somewhere before.

But, the doors creaking snapped you out of it. You could've swore that was.... wind? On the other side. But. That's not possible. Is it?

You clasped the handles and pushed them open. 

...

...

...Snow?

This is pretty cool, you admit. It shouldn't be possible, but yet it is! You bend down and touch the snow. Yep. You shake it off of your hand, now covered with white flakes. It was cold. So it was real.

You stand up and take a step in it, watching your foot slowly sink into the snow. It crunched just like it. It was so cool! Pun intended.

Watching your steps, you keep going......for three steps.

Then, you see something glint out of the corner of your left eye. A camera? Are there other people here?

You step over to it, pace quick, but determined. It was a camera, that was true. But you couldn't reach it. On the sides, it said 'W.D.G'.

You wonder what that stands for.

But....You get this odd feeling. Like someone is watching your through the camera. You smile at it, and walk away. No need to disturb something that's not yours. Especially if they are watching.

Again, you keep walking, paying mind to your surroundings.

You come across a tiny bridge. From first glance, it doesn't look that hard to cross. Maybe just cross it quickly. The bottom doesn't seem that stable.

Wait, what was that under it? You get closer, then kneel down. You can't quite see what it was. You lie down. Your stomach was gonna be cold and wet, but you were curious. 

Dang it. Just a piece of trash. A mustard bottle wrapper was torn, and the shiny inside had shown off from the lighting.

You go to stand back up, but can't. A pressure on your back is suddenly keeping you down. 

Back pain? It wasn't uncommon for you.

"heh."

Nnnnnnnnnope!"

"normally I break em' in 'fore they're on the ground beggin'."

You try to turn, but the pressure gets worse. It kind of hurts.

You can't move, so might as well asses the situation verbally.

"Can I at least look at you while you flirt with me?"

"heh. I like a girl who asks. sure dollface, get a good look."

He, obviously a he, by the deep voice, commanding, yet not quite threatening, loosens up on your back, but doesn't quite let go.

You take advantage of it, and fully turn around, so your back is on the snow instead. Must be a great show, since your shirt is fully soaked.

But when you turn, you aren't expecting to see what you see.

A towering skeleton, wearing shorts, a shirt and a black hoodie, glaring down at you. That. That is what you see.

You don't freak out. No point. You just tilt your head in confusion.

He seems almost happy.

"ya already like checkin' me out huh?"

"Well, no, but, I am curious."

He puts his foot back on your stomach, harder this time. You don't react, but it hurts to breathe a little bit more now.

"wanna see then?" 

You were curious. What did he mean? Do you want to see what this place is? Do you want to see what he looks like when he's not towering over you? Yes, to all of those.

"Sure.", you say, without thinking.

"no rush doll, but I gotta be somewhere with someone in hand soon, so let's get this over with, m'k? we both wanna get to the fun part anyway...."

"O-k?"

"heh. you're gonna be fun. I run this bitch. people do what I say, or they go away. so. You gonna do what I say?"

This suddenly doesn't feel very safe. But....Even so.... You're curious. You lay out your options.

Possible death because you resisted. Horrific things, possible, because you went along with it. The latter has you living, so you should run with that.

"I see. Fine. What do you want? You have me under your thumb. Or, shoe, in this case."

He chuckled a little. Alright, so he wasn't all business. You could work with this.

"good kitten. pants. off. now."

You grit your teeth. Life and death we're talking about here. Bear it. You do as he says, sliding down your pants slowly. Must be a good show for him. Shirt soaking wet and pants coming off. He seems satisfied, but now you're freezing cold. 

"funny. you act so obedient, yet you haven't been trained yet. this is gonna be fun."

His eyes, or, eye, glow red. You feel yourself moved, or rather, shoved, by an unknown force against the wooden pole near the bridge. The rough treatment is unwanted, but you grit your teeth and bear it.

"now. ur gonna stay nice and still while I have a little fun. who knows? maybe ya can have fun, too. just make sure if you do, I can hear it."

He gets uncomfortably close to your face, and presses his teeth against your lips. It feels similarly to kissing a hardcover book. 

His other hand trails down slowly, under your shirt. He grabs roughly at your chest, and you hold back the whimpering squeak. He pulls back his face an inch and smiles, before resting his head on your collarbone to enjoy the show he was orchestrating.

After doing it again to the other side, his hand crept down to your stomach, passing that part you hate, and stops just before going down under your underwear.

He looks back up at you, one eye practically flaming red. It made you blush so hard, you're sure he saw it.

"I want you to beg. beg for it."

You look into his eyes, waiting for him to show any hesitation. None. He was seriously waiting for you to beg for this. He wanted you to beg for something you..... didn't.......want. 

But......didn't you? You were letting him get this far. You could have easily chucked him over the bridge by now. So why didn't you? 

"kitten. M' not a patient guy. Beg. Now."

Screw it. You didn't know why, but trying to work it out was going to get you killed.

"Please....Tell me your name..."

"heh. guess it's a bit too early for ya to call me 'master' huh? name's Sans Dollface."

In the most lustful voice you could pull off, you whispered: "Sans. Please. Do whatever you want to me. I'm begging you. Please, I want to please you."

"woah, there kitten, you're a bit too good at this. but alright, since ya asked so nicely."

He threw his teeth against yours again, but this time, something slimey dragged along your lips, pushing them apart. You let it happen.

Just like you let the hand on your lower stomach dip into your underwear. You could feel the rough digets roll against your clit. You felt them crawl down to your entrance, teasing you, but not going in.

They went back to rubbing your clit, and hard. You gave out a tiny moan, one you thought wasn't audible. It was.

"c'mon babygirl, M' going easy on ya. ya want me to be rough?"

A single rear rolled down your cheek. You nodded a little.

"aight. ya asked for it Dollface."

The hand that was previously pressed against your chest slipped down and started working on your clit, while the one previously doing that slid down and slipped inside of you.

Your clit was getting the roughest treatment. He was furiously stimulating it. It felt so sensitive. You couldn't help the second moan that made it past your defenses.

"heh. kitten likes it rough, huh?"

You didn't respond this time. He didn't take offense to it. You probably looked like a bitch it heat. You were sweating and twitching against him. He was probably the only thing keeping you from falling into to the snow. Or down over the edge of the bridge for that matter. 

The other hand kept working on you. His digets kept rolling against your walls, including against the g-spot. Once he found it, as evident by a sudden loud moan that surprised even you, he kept working on it.

He kept going. He was hitting it harder and faster, while he was doing to same to your clit. You felt yourself build up. 

He kept going. Harder faster. It almost hurt. Scratch that. It did hurt.

But it was masked by the sudden explosion of pleasure. 

"cum for me kitten. that's it. make some noise, huh?"

You let out a long, drown out moan as you came in his hand. It wasn't loud, but it satisfied him anyway.

"that's it babygirl. no one here but us."

He was still going, slower now, but still going. It made you writhe in his arms; Twitching from the intense treatment.

"aight Dollface. ya gotta get dressed. ya got somewhere to be."

...

.......

"kitten?"

Passed out that's what you did. You still heard him talk, and could feel some of what's going on. But your eyes were closed, and you couldn't move. Nothing to do now but wait and see what he'd do.

"guess m gettin' ya dressed."

You felt him gently set you down in the cold snow, shortly followed by goosebumps running up and down your legs and arms.

You heard the rustling of clothes, and felt your own go back on your legs.

"now, c'mon kitten, boss wants to see ya. but I've got a feelin' he's gonna see how much fun we're havin' and get jealous. you're such a good kitten after all."

You felt him pick you up, bride style. You heard him sigh, and felt the hot air from him on you. He was surprisingly warm. You felt yourself drifting off, finally going into full on pass out mode. You let your bones relax. 

"c'mon. I know a shortcut."

**Notes for the Chapter:**

> I'm taking suggestions for the next chapter! Can be SFW or NSFW; your choice! Let me know in the comments below!


	3. Interested

**Summary for the Chapter:**

> After Sans' has some fun, Gaster orders the human to be taken to the MDC (Magic Deprivation Chamber). But, he orders them not to be turned on.
> 
> Reader is in for a surprise when Gaster shows up for a little visit.

Gaster kept staring at the human, and at the soul attached to it. He had never felt this confused before.

Even after Sans' little......performance; the humans' soul kept glowing, and it had only gotten brighter during the show he put on. 

In the past, when Sans' had done his dirty deed, the souls usually dimmed, and the human usually completely resisted when he tried to push it.

Sans had definitely pushed it with this one, even though he instructed him not to.

Sans shrugged him off, something about this one "being different". 

And he hates to admit it, but Sans was right.

This one was different. She seemed open, even willing, to do what Sans was doing. 

Maybe not out of desire, but maybe out of self preservation? But that couldn't have been. The soul would have shown up as purple: Perseverance.

God, this whole thing was throwing him off. Every human was supposed to be a part of the main colors. Green, Kindness. Yellow, Justice. Purple, Perseverance. Light Blue, Patience. Dark Blue, Integrity. Orange, Bravery. And Red. The dreaded Red; Determination.

But this one wasn't showing up as any of them. It was one that hadn't been seen before.

It was the unknown. The things from which new knowledge was born. It intrigued him. Enough to send Sans. 

...

Who should have been back by now...

"hey boss."

He jumped a little, but quickly shifted it into anger. 

He stood firmly, his arms behind his back, and a scowl on his face.

"Where were you? You should've been here by now!"

He squinted at Sans, daring him to make an excuse. He had seen everything on the cameras. And he knew that Sans knew.

"what? M' not allowed to have a little fun?" 

He looked at the human for the first time. She was rather pretty, but he was still angry. She was passed out. That's not what he wanted. He wanted her awake, ready for testing.

"Sans."

"yeah yeah, boss. sides'. ya saw how the soul reacted, huh? told ya it was different."

Ugh. As much as he hated to admit it. Again. Sans was right. He sighed, and turned from Sans. He would deal with him later.

"Bring her to the MDC. But leave it off for now."

"ya sure, boss? last one didn't do so hot in there."

"I will not repeat myself. Do it."

He felt Sans disappear, presumably to go follow his orders.

\---------------------------------------------------

You blinked once. You didn't see anything..

You blinked again. You saw spots of Red. You blinked several more times, but still only saw the spots of red.

You sat where you were, confused at ever.

You seemed to be propped up against a wall, which felt soft against your back.

You moved your toes, testing your body like a race car getting ready for a competition.

Yep, they worked. You moved your fingers next, curling them against the soft flooring. It seemed like the entire room was made out of these soft panels. And the walls all looked like they had these red lights in the middle of each panel.

Red light was hotter than white light. An energy saving thing? But why?

You couldn't quite stand, but you took a closer look. The light seemed to be pulsating. Like they were alive. It was freaky.

After a few minutes of steady breathing, you shifted your legs, and sat on your knees. Your head was spinning. This room was boiling hot, and it made your head hurt. It was difficult to breathe in here. 

Shortly after you shifted, you heard a click from the other side of the room. Then another click. And another. Getting closer.

Footsteps maybe?

You heard the steps come closer until they felt eeriely close.

.......

You heard another click, louder this time, and not the same as before. The click of a lock turning?

......

A place where you thought a solid wall was slowly creaked open. You couldn't see who was doing it, but you saw that the door led to someplace else. Someplace lit up in completely white. Similar to a doctor's office.

The shadowy person approached slowly. Cautiously.

They kept going until they were standing above you, but not touching you.

You saw that they were wearing a lab coat, and some formal wear underneath.

You cocked your head to the side. It seemed odd. They seemed tall and threatening, but hasn't done anything to warrant fear in you. The person tilted their head in response.

You stared at them, they stared at you. You felt that if you stared hard enough, you could see what their intentions were.

Instead, they leaned down, so that you could get a good look at them.

Another skeleton, huh? But this one gave you the chills. He had a crack going up from his right eye to his forehead, and another from his left eye to his chin. It felt disturbing.

He smiled at you, the crack on his left eye shifting with him. It didn't seem possible, but yet here it was, happening really.....really close to your face.

"Interesting..." 

His voice. God his voice. It terrified you. He didn't have to shout to get you to listen. You thought it was hard enough to to breathe. Now, it feels like he's already got his hands around your throat.

"Oh. Now you're scared."

Shit. He noticed. You felt the tension in your stomach worsen. This was terrifying. HE was terrifying.

"You like my voice, do you?"

You kept quiet. Maybe if you didn't say or do anything, he would go away. Yeah, right. He was probably the one to bring you here.

"I see. You're scared by me, aren't you? As well you should be. It will keep you alive down here."

His left arm, resting on his back, slowly moved to touch your face. You contemplated biting it. But you couldn't will your body to move.

Instead, you let his boney hand trail through the thick air, and down to your neck. He didn't put any pressure on it. He just rested a single finger on your windpipe.

"Hmmmmm..."

He never took his eyes off of you. 

..................

Suddenly, his other hand reached down and grabbed at your crotch. You let a little yelp past your lips. He smiled at you, the crack stretching even more.

In the deepest voice you've ever heard, he leaned in and whispered to you:

"Tests later." 

You felt him bite down on your neck, not enough to draw blood, but enough to leave a mark. 

You heard a gutteral growl in your ear, and it sent shivers up your spine.

"Fun now."

**Notes for the Chapter:**

> Man, I'm so pumped about this, I've been non-stop writing for the past hour!
> 
> Give me some ideas for a chapter, and I'll gladly do it! :)


	4. Slut

**Summary for the Chapter:**

> Gaster does his tests. And has his fun.

He pulled back, grinning devilishly once again.

"Then again...."

Oh God, what now? The last time someone said that, it ended up with you twitching on someone's hand. 

Just thinking back to Sans and the bridge made you shiver. The way he talked. It wasn't anything close to dirty talk, but it felt like every word he spoke was getting him closer to thrusting inside of you.

You start thinking about how a skeleton would have a dick, but the one in front of you spoke again.

"I am a man of my word. I promised to come in here only to start the tests." 

You relaxed your muscles a little. A scientific guy. A doctor? 

Doesn't matter. This one you can reason with. Besides, he'd have the most information. Maybe you could finally figure out what was happening.

I mean, first a talking flower, then a fiery goat lady, then a pervy skeleton, and then this bullcrap. Like, give me a break here.

"I should start the tests....."

Tests? Doesn't sound too fun. You never liked going to the doctor anyway.

"But that doesn't mean I can't still have me own fun."

You were about to tilt your head in confusion, when he leaned all the way back up, to full standing position. Was he always this tall?

You saw his chest rise and fall, him presumably taking a breathe. You didn't know skeletons needed to breathe. Then again, nothing made sense here.

And even though you were almost blind in this room, the red lights certainly got brighter. You looked over at the wall behind you, then back at the skeleton.

Your eyes widened when you saw what he had done.

Coming from his back, were two, no, four, things? Tentacles? Was that what they were called?

They looked like four jet black snakes heading straight for you. You panicked, and tried to press against the wall. But there was nowhere to go.

In the light, they looked slimey. And when one of them reached your face, it felt like it too.

You were practically having a heart attack. The one by your face gently rubbed along your lip.

You saw a hand with a gaping hole in it taking notes on a clipboard. It was separated from the skeleton, and that's what freaked you out.

Why was everything so freaky and weird?

"Hmmmmm..."

Oh, what now?!

The one tentacle pulled away. You were still tense, and looking for a way out. But you didn't move.

Some freaking crazy part of you was curious. You didn't really want a repeat of Sans, but this one seemed different. Curious, like you, and not as lust-driven as Sans. It made you almost respect him.

"Funny."

You decide, after a comfortable 3 seconds, to test your luck.

"What?"

He raised an eyebrow, however that was possible. Just don't question it. Things will go a lot smoother if you didn't.

"Why haven't you run? That door behind me has been open for quite some time now."

You couldn't look at him. Not while the tentacles on his back kept slithering about. They hung at his side, but still moved, like a tail of a lizard after you cut it off; Just silently and slowly moving about.

"I. I. I don't know."

"Fear? No. You don't seem scared."

You laughed a little. You sure about that, buddy? Cause I'm TERRIFIED.

"Morbid curiosity, maybe?"

You kept quiet. I mean, he might be right. The door's been open. You were probably fast enough. He didn't seem that agile himself.

"Let me try something, human. I promise it won't hurt. And I haven't earned it, but you have to trust me. Ok?"

You looked at him. You couldn't find any reason not to trust him. He had you backed up against a wall, anyway. Better to agree than to not go along with it, and have it happen anyway. You nodded.

"Ok. Now, sit up and sit still."

You did as he said, sitting cross-legged, and taking a few deep breaths as to try and still yourself.

.......

You saw him mumble something to himself, and then you saw the disembodied hand write something down. That thing still creeped you out.

"Try closing your eyes and relaxing."

"Easier said than done."

"Just try. I want to test something."

You did what he said again. But this time, you felt something in your gut. It didn't hurt, but you had never experienced this before. You kept your eyes shut.

The feeling continued.

......

 

"I've never seen anything like this before. You can open your eyes now."

You did, and you're glad you did. What you saw was absolutely stunning. A hazel colored cartoon-like heart was floating in front of you. It shimmered, and lit up the entire room.

Even the doctor seemed in awe. He was looking at it from all angles, and the hand was furiously writing notes.

You finally spoke up. 

"What is this?"

"It's your soul. To put it in the short version; It's everything you are. But I've never seen one this color. And I think I've figured out what yours is."

He mumbled the last part. You just barely heard it. 

"What does it do?"

He raised his eyebrows, then came back his devilish grin again. You feel your sins crawling on your back as you try to shove yourself back into the wall.

"Well. That depends on the welders intention. For instance. If my intension is to hurt..."

You saw him grab the heart and give it a little poke. Instantly, you felt like you had just been punched in the gut. It hurt. It hurt a lot. You curled up into a ball on the floor. You were rocking back and forth, feeling the ground against your cheek, as well as the swarm of oncoming tears.

He let go of it, and it all stopped. You were slowly uncoiling yourself against the floor. You didn't even notice the tentacles creeping up on your back.

You barely noticed as they started to slowly remove your clothing, starting with your pants, making sure to move as slow as humanly possible. By the time you were fully functional, you had already lost your pants and shirt.

"Or."

You braced yourself again, ready for the pain this time.

......

 

Only. It never came. Instead, a steady stream of pleasure came when he picked it up. In your trance of pleasure, which was greatly appreciated after the unexpected pain, you noticed the clipboard, which had a steady input of notes coming in. 

And on the back of it, you saw the letters: G A S T E R

Gaster? Was that his name?

"Gaster? What did you do?"

He looked on the back of the clipboard, also seeing his name.

"Very observant. And I did what I said I would. I can make it hurt with one touch. Or, I can do this."

He then began caressing it gently with both of his hole ridden hands. Waves of pleasure started coming in. You were rocking back and forth, in time with them. 

This time, you felt the slimey tendrel press up against your crotch, rocking back in forth in time with you.

You were already soaking wet, and this only made it more so.

One of the slimey black tentacles gently pushed your chest so that you were leaning against the wall.

"See, babygirl? I can make it feel really good. Do you want more?"

You didn't, or in this case, couldn't, nod. A lust filled calmness washed over you.

"I'll just take one where I can get one right now, little one."

 

You saw the heart shine brighter every time he spoke.  
And at the same time, he started kneeding it, like a cat with a silk blanket. It felt like a miniature orgasm every time he kneeded deep into it.

And the tentacle rubbing your crotch slipped under your underwear, and started doing the same thing to your clit.

Another one, extending from his back, started slowly poking it's way inside if you, prodding at your entrance.

You showed no resistance. You were soaking wet, practically begging for someone to do something to you; To get any kind of physical stimulation.

He obliged once he heard you moan.

"Good girl, moaning for me. Moaning for your Master."

That's right. He was here for you. He was going to give you what you wanted.

You moaned louder, egging him on. It worked. Hah. Basic phycology. Works every time. Let them believe they are in control here, and let them do all the work.

The slimey tentacle entered you, and began slowly pulling in and out of you.

You were practically on the edge already. He kept doing something to your soul, and it felt like he was giving you the best oral ever.

You saw him open his mouth, and nibble on it. You nearly threw your head back into the wall. 

"God. Please-"

"Ah ah ah. Good little pets ask nicer."

He seemed serious, but never stopped stimulating you. The tentacle actually moved quicker, sliding against your walls, slithering about in them. He was rubbing everywhere in you.

Not this again, you thought. Gaster and Sans weren't that much different after all. They both wanted you to want it.

"Daddy Gaster!" You moaned out. You were almost to the point of no return. Better make this begging thing quick.

"Master! May I please please please cum for you? I really really want to!"

He sped up on your clit a little, sensing you were still sensitive from Sans. The tentacle thrusting inside you spend up, too, still slithering against your walls, but more focused on your g-spot now.

Gaster smiled as he watched you slowly unwind mentally, reduced to a little whore for him.

"My little girl sure does know how to beg."

He bit into the soul, harder now. "Cum for me, my little slut."

He growled loudly, then bit into the soul once again, harder and for longer this time.

Something inside you snapped, and you screamed. You came so hard, and he never stopped thrusting in you. He looked at you with devilish eyes, but kept his teeth in your soul.

"That's what I wanna see. My little pet is still cumming, huh?"

He was right. You were still cumming. He didn't stop until you started twitching and tears started rolling down your cheek. It was the most intense orgasm you've ever had.

He slowed down, and pulled out of you while stepping closer.

You were a panting, sweaty mess, and just about ready to pass out again.

He stepped over to you, which wasn't saying much. He was standing over you the whole time, scratching notes on the clipboard, especially while you were cumming.

Though, in all honesty, he was more focused on either your soul, which he was now returning to you, or on your lust ridden face.

The second the soul had disappeared inside your chest, you felt calm again. You grabbed your shirt and pants, suddenly feeling modest. He looked at you, but then sighed and looked away. You assume that was the all clear for dressing again.

"Interesting. I was correct. The tests were indeed conclusive."

Test? 

"You mean this whole thing was just some stupid test?"

You covered your mouth the second you uttered those words. You didn't even mean to say anything.

He didn't seem offended, though.

"Yes. Your souls nature is clear now."

"What?"

He sighed again. "Long story short, all souls have a color and a matching personality trait. Green means kindness, Yellow, justice, so on and so forth. Yours has never been seen before."

You couldn't tell where he was going with this. He kept explaining, anyway.

"Most souls nature can be revealed through certain situations. This was one of them: Sex. Yours was revealed to be hazel, which is a combination of Determination and one we've never seen before: Curiosity."

He sighed again. But he looked at your face. You didn't think you looked confused. And apparently it showed.

"Good. You understand to some extent."

He turned and started to walk away. You stood, fully clothed and able to walk. He stopped and turned his head back around to a creepily level. One's head shouldn't turn like that. His voice dropped to a shockingly deep level as well.

"You will stay."

You tilted your head, but sat back down anyway. He now had your respect. He earned it. At least, he did in your eyes.

"Good. Maybe you wont have to be in here too long. You are so obedient after all."

He turned his head back, and started to walk away again. 

You saw the door close, killing what little light you had from the outside. The second the door closed, the wall lights turned from red to white. It felt weird. Disturbing, even. 

Like all the energy was being drained from you. You felt fatigued all of a sudden. Was it the lights doing it?

You lied down, back and head leaned against the wall. You deserved a nap after everything that's happened.

But you jolted up when you heard a familiar, but commanding voice echo in your head like a drum.

"See you soon, my little slut."

**Notes for the Chapter:**

> Alright, so someone asked for tentacles, and honestly, I already wanted to try writing them. 
> 
> I always imagined them as kind of thin slimey snake-like tendrils, so that's how I wrote them!
> 
> Side note: Finished with my family stuff! Got everything sorted out!
> 
> However, I probably won't be writing much from June to Late July. I'll be getting surgery, and will be recovering in a hospital for a few weeks. Thank you for your understanding!! <3


	5. Alphys

**Summary for the Chapter:**

> Alphys.
> 
> It was horrifying. The memory is burned into your skull. You would give anything to go back to that room and forget this ever happened. Anything.

"Why are these people so into my body?"

That was your question. Why the hell was every monster demon thing you came across so.....well...kinky?

You appreciate a good fuck now and then, but this was getting out of hand. 

"God damnit." You whispered. These lights were killing you. It felt like they were just sucking you dry, eating up what little energy you had.

You had to get out of here. This place would kill you if you stayed too long; you could already tell. And you weren't gonna stay put like a pet, although Gaster had already taken to calling you by that.

This room was dark and confiding, but it wasn't sound-proof. Every now and then, maybe every hour or so, God it was hard to tell time in here, you would hear Gaster outside. Only when you got close to where he left last time he was in here. Apparently that was the only exit.

Sometimes he would be with some meek sounding monster. He was doing most of the talking in his usual warbled voice. You had figured out how to make sense of it. But apparently, even some of his assistants couldn't.

They would almost always ask him to repeat stuff. It never got on his nerves, or at least it didn't sound like it. But it kind of got on yours.

You wanted to get out. From what you could hear, which was very little from the assistants, you were getting out soon.

Gaster never said your name, though he never even bothered to ask in the first place. He kept calling you different names, depending on who he was with.

You couldn't see them, but they all had different voices, most of them very distinguishable. So far, there were three.

One of them was the loudest, and could understand Gaster the most, though he kept quiet when Gaster spoke. Apparently, Gaster was the one in charge, and no one wanted to mess with him.

The second one was a girl, but kept to herself. She wasn't nervous, but she didn't sound as stupid as the last one. She seemed to only speak when spoken to. It was kind of disturbing. Like her tongue had been changed, swapped with another one. 

She sometimes spoke in this language you couldn't even hope to understand. But Gaster seemed to be able to. He even spoke it himself. It really messed with your head.

It sounds crazy, but every time you hear it, it feels like the person speaking it is in your head. Like you could feel them searching your brain for something. It freaked you out.

But the last one freaked you out the most. You only ever heard her speak twice. Once, to herself, and once to Gaster. 

Every once in a while, you heard Gaster walking around and talking with someone, but they never spoke. 

But the one time she did, something scary happened.

Gaster stopped talking. And started listening to her.

Gaster never stopped for anyone. He would constantly interrupt everyone. Except her.

That one time was all the information you needed; If you ever see her, do. not. fuck with her. No matter how curious you get. Do not piss her off.

\------------------------------------------

You were sitting by the door like usual, sitting there, waiting for another conversation to happen, hive you some clue as to when you were leaving. 

This was getting to be unbelievable unbearable. 

But, someone was starting to come down the hall. And it wasn't the usual Gaster strolling down. The shoes were different. Gaster's shoes were loud, commanding. These were soft and quiet.

They kept getting closer. Closer to the door. When they got a few feet away, you quickly shuffled to the other side of the room. Just in time....

The door opened. Outside of the door was a little yellow monster. A little bit chubby and with big glasses, like the ones in anime that shimmer when they fix them.

She didn't step inside. She just stood there, hand on the door, staring at you. She then pushed the door closed a crack, and leaned back down the hallway, keeping a sharp looking claw on the door, and one foot in the door.

She used her free hand and gave a hand signal down the hall.

She turned back to you, and kept staring.

You heard some mechanical sounds, like something powering down. And then it happened! Finally! The lights tuned off, going back to the color they were before.

You felt like the weights that were on your chest had been lifted. You closed your eyes and breathed a deep breath, smiling a little. You could finally breathe again!

Once you opened your eyes, you noticed that the monster got closer. What was she? A weeping angle? You blinked. She stayed put, still staring at you creepily. Nope. Not a weeping angle.

There was a long pause.

............

".....Gaster will see you now."

Shit. It was her. God damnit. Why her? Sure, Gaster, send in the one person your afraid of.

You had to follow her. She scared you, sure, but she wasn't all that big. If you wanted, you could take her. Bit you didn't want to. Besides, then Gaster wouldn't be very happy. Yeah, maybe you shouldn't piss off the guy in charge. You may be trapped in some place you don't know, with no sign of a way to get out, and stuck with kinky monster demon things, but you gotta think logically here.

Besides, if it meant you were getting out of this room, you would follow her. This room was horrible.

You went to your knees, and shakily stood up. How long had it been if you're having trouble standing?

"Ok. But, um, what does he want? And why didn't he come here himself? And why-"

"You certainly are annoying. Good thing Gaster likes you. I would've dusted you the second you turned up."

Shit. Did you just piss her off? Damnit. The first thing you said you wouldn't do, you did on the first sentence you said to her. Damage control.

"Sorry. I didn't mean to annoy you. I'm just not getting any answers here."

..............

"And if you're smart, stay ignorant."

She signaled you to follow her as she silently stepped out of the room, beckoning you to follow. You did. Your damage control worked hopefully. But you didn't want to take any chances.

You kept following her down the long, eerie hallway. It was disturbingly white, but had dust on it, like no one had touched it in years.

This was so frustrating! No one's talking you you, no one's telling you anything! You've thought up several questions in that room, and have gotten zero answers so far!

You were curious, damnit! And god knows it killed the cat.

"Can I ask you one question. Nothing about Gaster, I promise."

She didn't stop, but you saw her left arm twitch. She was walking towards a big steel door, with a lot of markings on it. They looked like those ancient markings outside of Mt.Ebott. Most disturbingly, claw marks all along the wall; like a rabid monster had been set loose...

Or worse.

.................

"One question. Go."

You answered right away, sure of your question. If you weren't gonna get any useful information, might as well try and get some maybe-helpful information. Maybe you could get some-what friendly with her. Maybe in the future she could help you. And this might just be the first step. Maybe....

"What's your name?"

She took one step, stopping just short of walking straight into the door.

She put a hand on the door softly. You heard her sigh. It sounded so sad. She started to push the door open. The door was eerily quiet. It looked old, and you thought it would make a lot of noise. Nope. Dead. Quite.

A familiar looking hazel was shining through the crack that was slowly getting wider as she pushed the door open a little more.

It looked so familiar. Where had you seen that color before?

She pushed the door open all the way. 

And what was inside. You will never forget.

....................

...................

"Alphys......."

God. It was horrible. The image of it burned into your skull.

 

...............

 

"And I'm sorry."

**Notes for the Chapter:**

> Hey guys. So I'm sorry this chapter has been so delayed. I've been dealing with depression, and lately it's gotten really bad. I've been cutting myself and I've felt my motivation plummet. I'm trying to reach out to friends and get help, and so far I've found one really supportive one whose helping me through this tough time.
> 
> So, in conclusion, I will be continuing Curiosity, but, I can't post as often as I'd like. 
> 
> Thank you for understanding and being patient with me!


	6. Souls

**Summary for the Chapter:**

> What's behind that door?

Hiding behind that wreched door, it was a horrific sight. Like one straight out of some twisted school boys fantasy.

Small glass domes, like a sort of twisted terrarium, sat up on small platforms. The platforms were slightly raised off the ground, and had tiny steps leading up to the glass.

Inside...

God, it made you want to throw up. 

Inside were..... children. Actual living breathing children. Some looked asleep, some looked dead. Some were alive, looking straight at you, like they were waiting for you to react.

Oh, you reacted.  
You wretched, and felt your gut tremble. Your knees suddenly couldn't hold you up.

Oh, but lucky for you, the second your legs started to give way, you felt hands grab under your arms to stop you falling headfirst.

The cold hands grabbed your waist, but not in a sexual way; just to keep you up.

You don't have to look to know. Sans. 

You couldn't even take your eyes off the sight. It disgusted you. Children, very young children, maybe 10 years old, held trapped in cages. Some of them had scratches on them. And they didn't look natural. They had an aura that made you want to cry.

Just how many were there? You counted them quickly. 

1, 2, 3, 4, 5, 6, 7

Seven poor souls down here. God, what if they had to go through all that horrible.....adult.... stuff.

You barely made it out with your sanity. Jesus, what have these kids home through.

You ripped yourself from your pitiful gaze, and threw Sans' hands away. You ran over to a dome, before anyone could stop you.

Even running for a few seconds was tiring. This was bad. You were going to lose yourself if this kept up.

With a closer look, the glass was thick. Too thick to break.

And there was an orange tint on the one you were pressing your hands against. It was barely noticeable, but up close it was very distinct.

The one inside of this one seemed ok. Maybe he was just the brave one? There was always the brave one.

You were never the brave one.

He stared back at you. Could he hear through this? He moved his lips, but you couldn't hear him.

You felt a cold hand on your shoulder. Turning slowly, you look up to see Gaster's frightening gaze starting back at you. His eye sockets were dark. Too dark. They looked like an endless abyss, and you just looked straight into them.

"I advise you to never do that again. Or we will have a problem."

You gulped, and shakily nodded. With him standing over you, you felt your life hanging over a cliff.

He gave a rotten smirk that sent shivers down your spine. The left side of his cracked face moved, but his eyes remained staring into your heart.

He blinked (how?) and turned his heel.

Alphys was still at the door, and you looked at her for help.

Like you suspected, she turned her cheek. Literally. She turned and walked away, in the same direction as Gaster.

You stepped away from the dome behind you. Damnit. He saw all of that. You were his only hope, and he just saw you practically lick Gaster's feet and call him Master.

You turned back to him and gave your best smile. It probably looked pathetic.

But instead of looking at you angrily, he started doing something else.

He started making hand signs, but not like the ones Gaster uses. Hell yes! He was doing sign language! You understood the basics, so you could probably figure this out! Thank God for your late night curiosities!

He seemed to be signing only in the alphabet.

S-A-N-S F-R-I-E-N-D

Certainly seemed a bit TOO friendly for your taste....

He kept signing, despite your confusion.

G-A-S-T-E-R B-A-D B-U-T F-O-L-L-O-W

If he was bad, why should I follow him? He seemed not too keen on your health, and more on his science and tests. Maybe he meant I should follow along with Gaster's plans, but not to trust him?

A-L-P-H-Y-S B-A-D A-V-O-I-D

Ok, so stay away from Alphys? Was she bad? I mean, she didn't seem afraid of Gaster, but she didn't seem bad or anything.

The kid looked up, then suddenly turned around.

You turned to look, but felt a sharp pain in your neck. You didn't know why, but suddenly your vision kept blurring, and it got immensely difficult to keep your balance. You knew that feeling. You never liked needles.....

"sorry kitten, it'd be easier for both of us if ya weren't awake. doc's orders."

Sans. God damnit. I thought the kid said he was your friend?

You got one thing out of your mouth, which was getting dryer but the second.

"What...are you gonna....do.....with....me...?"

You felt his hands on your hips, supporting you, and slowly lowering you to the floor.

"well, if I got a say in this....you'd be back at my place, getting something other than a needle shoved in ya."

Your heart started racing. God you hoped he didn't mean....

"well, food fer starters."

You audibly sighed. He chuckled. His voice was low, and his laugh was somewhat comforting, though a bit scary.

"don't worry Dollface. I like ta warm em up for I do anything serious."

You were laying on the floor fully. Sans was sitting to your right, petting your hair, probably waiting until you finally passed out.

"don't worry kitten. I'm more interested in that soul of yours than your body. Though that's pretty nice too..."

He practically purred that last part.

You had your eyes halfway closed, your body losing consciousness.

"more importantly....you might be the one gettin us outta here.... I ain't gonna lose you like these rats..."

He growled, and it probably would've scared you if you weren't drifting between consciousness.

"yer soul is special. very. special. I fucking love it. I fucking love how it shines for me. and only for me."

"and I ain't gonna lose you to that lab-coated science whore."

**Notes for the Chapter:**

> Yeah yeah, I'm delayed, I know. But hey, *sings* It's gonna be May!


End file.
